Mill



Nov. 6, 1928.

F. E. MARCY MILL Filed June 7, 1927 2 Sheets-Sheet l QVENTOR ATTORNEY S,

Nov. 6, 1928.

1,690,493 F. E. MARCY MILL Filed June '7, 1927 2 Sheets-Sheet 2 G/ INVENTOEVz ATTURNH S.

Patented Nov. 6, 1928.

UNITED STATES PATENT OFFICE.

MILL.

Application led .Tune 7, 1927. Serial No. 197,054.

My invention relates to an improvement in reducing mills, in which the material to be reduced is confined within a rotary drum or barrel together with the reducing medium which may be in the form of balls, pebbles, cubes, rods, etc. These mills may be employed for Wet or dry grinding, the material being crushed or reduced by impact and attrition, as the mill load tumbles and cascades due to rotation of the mill drum.

One of the objects of my invention is the provision of a mill of the type above indicated in which the balls or other reducing medium, in addition to theirl usual cascading movement, are given a lateral movement.

Further objects of this invention are the provision of means to give a more circuitous travel to the balls or other reducing medium, and to prevent the reducing medium from traveling in the one path and from becoming wedged against the ends of the mill, all of which results in increased efficiency of operation. In mills of the type to which this invention is directed there is a constant migration of the mill load toward the discharge end due to the continuous feeding of material to the feed end of the mill drum and the constant discharge of material from the discharge end. The present invention not only provides for increasing this migrating action, but provides fora lateral movement of the load in the opposite direction, i. e., to-

ward the feed end, resulting as above stated, in a more circuitous travel of the mill load and effecting a marked increase in the discharge of fines or reduced material.

A still further object of this invention is the provision of a mill of the character indicated in which the reducing action is increased as compared with the reducing action obtained in mills of this general type prior to my invention, due to the fact that a lateral surge or movement is imparted to the mill load tending to throw the oversize material toward the center of the mill drum where the reducing action is most pronounced.

A still further object of my invention is the provision of a reducing mill having its interior provided with members projecting inwardly of the drum, these members being so constructed and arranged that a` lateral movement is imparted to the mill load, i. e., the balls, rods or other reducing media employed and the material to be reduced, this lateral movement being increased by the application of my invention to both ends of the mill. As a result, the load is given a greater travel than heretofore, is kept more centrally of the mill where the reducing action is maximum, and Works the oversize away from the discharge end of the grate, thereby preventing plugging or blocking of the grate and facilitating the discharge of the fines therethrough.

It will be seen, therefore, that it becomes an object of my invention to provide a mill of the general character above indicated in which movement or migration of the entire mill load toward the discharge end is accelerated or expedited; and to provide means for moving the reducing medium and oversize away from the discharge end and grate thereby to reduce plugging or blocking of the grate openings by the oversize and reducing medium, and permitting` the fines to es cape from the mill through the grate opemngs.

Other and further objects of the invention will be brought out in more detail hereinafter.

In the drawings accompanying this application, I have shown my invention applied to a ball mill, that is to say, to a mill employing balls as the reducing media. Itis to be understood, however, as I have Yindicated above, that a ball mill, has been shown for purposes of illustration only, and this showing is not to be considered definitive or in any way as limiting my invention.

In Figure 1 I have shown in sectional elevation a mill of the ball type, in which one form of myimproved construction has been incorporated Fig. 2 is a cross-section through the mill of Fig. 1, looking toward the discharge end thereof;

Fig. 3 is a section on the line 3.-3 of Fig. 2;

Fig. 4 shows a further modified form of mill;

Fig. 5 is a section on the line 5-5 of Fig. 4 looking toward the feed end of the mill;

Fig. 6 is a section on the line 6 6 of Fig. 5;

Fig', 7 is a part sectional elevational view of a further modification:

Fig. 8 is an embodiment of my invention n in a mill provided with radially extending grate slots; F Fig 9 is a section on the line 9-9 of Fig. 10 shows a still further modification;

Fig. 11 is a section on the line 11-11 of Fig. 10;

igs. 12 and 13, respectively, are sections of different types of defiecting members adapted to be incorporated in the mills of Figures 8 and 10. for example;

Fig. 14 is a still further modification of the construction shown in Fig. 1; and

Fig. 15 is a section thereof taken on the line 15-15 thereof.

Referring to the drawings in detail, and first of all to Figs. 1 to 3, inclusive, 1 designates the barrel, drum or shell of the mill, this drum or barrel being provided with a A discharge head 2 and feed head 3 and with discharge trunnion 4 and feed trunnion 5. This construction is usual and will not be described in great detail. It will be sufficient to state at the outset that for purposes of illustration, and not by way of limitation, I have shown a mill of the ball type, that 1s to say, a mill which in practice is charged *with steel balls, for example, and with the material to be reduced. the rotation of the drum causing the balls and the material which is to be reduced to tumble about in the drum, thereby effecting the desired reduction.

As I have indicated above, however, I have provided means whereby the reducing action and efficiency of the mill may be greatly increased without increase in the power requlred for operating the mill and without incurring additional expense by way of increasing the load of reducing medium.

The mill drum, barrel or shell 1 is provided with sloping liners or liner sections 1` having a spiral formation or contour on the wearing face, i. e., the face adjacent the interior of the mill, the spiral formation being in a direction to work the charge toward the discharge end of the mill. these liners or liner sections extending the length of the drum. The liners are stepped as indicated in Fig. 2. and shaped so as to fit the interior of the mill drum and to slope toward the discharge end or discharge head 2 and effect on the uptraveling side of the drum a migration of the material contained within the drum toward the discharge end. At or adjacent the discharge end of the mill. I provide grate sectors 6. These sectors are held in place about the discharge trunnion 4, being assembled about a cone-shaped member 10 by means of radially disposed clamp bars 'l' of improved and novel construction, wedge shaped in crosssection, as indicated at 8 in Fig. 3, while the adjacent edges of adjacent grate sectors 6 engaged by the clamp bars are likewise tapered so that when the bolts 9, by which the clamp bars are held in place, are set up, the grate sectors will be clamped to each other and to the mill to provide, in effect, a onepiece structure.

The clamp bars 7 extend inwardlj of the mill beyond the inner face of the grate sectors 6, as indicated in Figs. 1 and 3, the advance or leading face 11 of each one of these inwardly extended clamp bars being concaved or slotted or grooved throughout its entire length, as indicated at 12.

Upon rotation of the mill in its bearings in the direction of the arrow on Fig. 2, and assuming the mill has been charged with its ball load and is charged or continuously being charged with the material to be reduced, it will be apparent that there will be a forward movement or migration of the mill load toward the discharge end of the mill and a cascading of the load due to the rotation of the mill drum, the migration or forward movement of the load being accelerated by the employment of the liners 1 above referred to, and which, as above stated, are inclined or sloped toward the discharge head. This movement and agitation of the load effects the desired reduction of some of the ma terial to be reduced, and the reduced material or fines, as well as the oversize, together with the balls or other reducing medium employed will eventually reach the grate sectors 6, such of the fines as are free to do so escaping through the openings in the grate sectors into the space between the grates and the discharge head 2, to be raised by the lifters 13 until free to flow out the discharge trunnion 4, past the base of the cone 10. As so far described, therefore, it will be seen that the provision of the inclined spiral liners or liner sections 1 increases the migration of the mill load toward the discharge head with a corresponding increase in discharge of the fines through the grate sectors as compared with prior structures in which a smooth interior is employed.

As above pointed out, however, a still further increase in efficiency of operation is o btained. In the further rotation of the mill, the oversize, the reducing medium, and as much of the fines as have not yet found their way through the grate sectors 6, will be carried up by the deflecting portions of the clamp bars 7 aided by the groove 12 in each bar, this mass, when the angle of' repose is passed, tumbling downwardly upon the cone 10, some of the fines of the mass as they tumble from the cone finding their way to and through the grate sectors, while the remainder of the mass is defiected laterally toward the central part of the mill drum, to once more begin its cycle of movement.

It will be apparent, therefore, to those skilled in thisart, that there is a constant cycle of movement of the mill load during rolml tation of the mill drum, which I can best describe as a movement or migration toward the grates, a cascading movement due to the carrying up of the load by the mill drum and a lateral movement toward the central part of the mill. This cycle or circuit is not one of mere agitation or stirring up of the mill load as Will be obvious, and during such movemeans whereby the oversize is constantly being worked away from the face of the grates so as to maintain the same unobstructed for the free and ready passage of the fines therethrough.

Referring next to Figs. 4, and 6, I have here shown a modification of the construction embodied in the mill just described. The discharge head 2 and feed head 3 are in this instance conical with the base of the cone, in each instance facing the interior of the mill drum. The mill is provided with liners 1 extending from one end to the other of the mill drum and sloping toward the discharge end thereof. The grate sectors 6 are inclined inwardly of the mill instead of standing vertically, and held in place by clamp bars as in the case of Fig. 1. The central cone-shaped deflecting member 10 about which the gate sectors are assembled is retained.

At the feed end of the mill I provide end liners 14 shown in the form of sectors and held in place by radially extending clamp bars 12' bolted to the feed head by Bolts 1s. The clamp bars are shown in detail in Fig. 6, and from this figure it will be seen that the adjacent edges of the feed end liners are inclined toward each other, and that the sides of the clamp bars are similarly inclined so as to obtain a wedging action as the bolts 18 are set up, thereby to securely hold the feed end liners in place as a unitary structure. Each liner clamp bar is extended inwardly of the mill for its full length, as indicated at 15, and the advance face 15 is provided with a groove or slot 16.

Assuming that the mill has been charged with balls, for example, and the material to be reduced. and is set into rotation, in a direction toward the observer, as viewed in Fig. 4, the material contained within the mill drum Will be caused to cascade and tumble about to effect the desired reduction by impact and attrition, the clamp bar extensions 15 increasing the agitation of the load and effecting movement thereof toward the center of the mill drum While the liners 1 will effect, on their upward movement, a movement of the load toward the grate. The material as it reaches the grates will be screened thereby, some of the fines working their way therethrough, while the remainder of the load adjacent the grates will, due to the action of the grates and the rotation of the mill drum, be caused to cascade down upon the conical member 10, and by it be deflected toward the center of the mill, to leavethe grate sectors unobstructed by the reducing medium and the oversize, the load then beginning its next cycle of movement. In other Words, the mill load in this embodiment of my invention is given movement or `move ments similar to that imparted to the load in the embodiment illustrated in Fig. 1.

In this construction, it will be seen, I providlelz load deflecting means at each end of the m1 In the mill of Fig. 7, the discharge and feed heads 2 and 3, respectively, are identical with the corresponding heads of the mill of Fig. 1, extending vertically with respect to the longitudinal axis of the mill drum. The grates 6, assembled about a cone 10, are inclined outwardly.

The operation of this mill is very similar to that of the embodiment of Fig. 4.

In Figs. 8 and 9, which show in sectional elevation the discharge end of the mill, the slots in the grate extend radially of the head instead of circumferentially, as in the forms already described. The grate sections themselves are rectangular and are assembled about a cone 10. The space between adjacent grate sections is triangular, and in these spaces I provide load-deflecting clamping members 17, having their apices projecting into the mill drum for load-deflecting purposes.

As the mill drum is rotated, it will be apparent that the load will migrate toward the grate sectors, to be screened thereby, the fines passing through the grates, while the oversize and reducing medium will be worked away from the grates toward the center of the drum, to leave the grates unobstructed so far as oversize and reducing medium are concerned, as in the embodiment of Fig. 1, for example.

In Fig. 10, alternate grate sectors G are removed and substituted by load-delccting grate-clamping members 19, having their inner faces extending inwardly oi the mill drum beyond the inner face of the grates. These members 19, in conjunction `with the conical member 10, will function similarly to the members 17 of Fig. 8.

Figs. 12 and 13 show modified forms of load-deecting members which may be substituted for the members 19 of Fig. 10.

In Figs. 14 and 15, adjacent grate sectors are held in place by clamp bars 12 extending inwardly and laterally, eachextension completel overlying the adjacent grate sector. To a ord a support for these extensions, I provide legs 20 interposed between the trailing edge 21 of the extension and the adjacent sector. The extensions are perforated, as indicated at 22, to permit of the passage of material therethrough toward the grates. The extensions, therefore, not only deflect the load in the rotation of the mill, to return the oversize toward the center of the mill, b ut assist the grates in screening out the oversize.

It will be seen therefore that I have pro vided a mill structure in which the spiral liners, which are so disposed within the mill drum as to slope toward the grates, will effect a migration of the mill load toward the grates by an action comparable to that of a screw, this action being further accelerated in those embodiments Where dellecting members are employed at the feed head. It will be apparent also, that the discharge end construction, several forms of which havebeen described, will effect a clearing action with respect to the grates to prevent the latter from becoming obstructed by the oversize and reducing medium, thereby expediting the discharge of fines through the grates, the load apparently moving in a regular cycle, i. e., toward the grate while cascading due to the rotation of the drum, this movement being assured by the action of the spiral drum liners, a movement upwardly adjacent the face of the grates, and then a movement rearwardly due to the dellecting members, toward the drum center. This movement of the mill load as will be obvious to those skilled in this art, will very materially increase the efficiency of the mill, insuring a faster discharge of the lill fines by reason of the grates being kept comparatively free of oversize and reducing medium.

It is evident that various modifications may be made in the constructions above described within the purview of this invention.

lVhat I claim is:

1. A mill comprising a rotatable drum or f' barrel adapted to receive a load of freely movable reducing bodies and material to be reduced, a feed end and a discharge end for said drum or barll, a grate adjacent said discharge end, and load-deflecting means adjacent said grate and cooperating therewith for freeing the grate of oversize during rotation of the mill.

2. In a mill of the class described, the coinbination of a rotary drum or barrel, a feed head and a discharge head therefor, a grate adjacent said discharge head and load deflecting means for the mill load adjacent the discharge head, disposed radially thereof and cooperating'with said grate to free the same c of oversize.

3. A mill comprising in combination a rotary drum or barrel, a feed head and a discharge head therefor. a grate adjacent the discharge head, a load cooperating upon the mill load during the rotation of said mill, and

deflecting means within'the mill and cooperating with the grate for increasing the discharge of fines through said grate.

4. A mill comprising in combination a rotary drum or barrel, a grate adjacent the discharge end thereof, and deflecting means cooperating with said grate for deflecting the oversize and reducing medium inwardly of the mill in a direction opposed to the normal direction of travel of the mill load.

5. In a mill, the combination of a rotary drum or barrel, a feed head therefor, a grate adjacent the discharge end, said grate being made in sections, and members interposed between the sections of the grate for securing the grate sections in position, said members extending inwardly of' the mill, beyond the inner face of the grate sections and cooperating with the grate to free the same of oversize.

6. A mill comprising a rotatable drum or barrel adapted for the reception of a load of freely movable reducing bodies and material to be reduced, sector grates at the discharge end of the mill, and load-deflecting means about which the grate sectors are disposed and co-operating with the grates to deflectthe oversize of the mill load laterally to increase the discharge of the fines of the load through said grate.

7 A mill comprising a rotatable drum or barrel adapted to receive a load of freely movable reducing bodies and material to be reduced, a conical member at the discharge end of the mill and disposed centrally thereof, grate sectors disposed about said conical member, and means projecting inwardly of the mill be ond the inner face of the grate sectors andYco-operating with said conical member to free the grate of oversize.

8. A mill comprising a rotatable drum or barrel adapted to receive a load of freely movable reducing bodies and material to be reduced, grate sectors, a conical member located at the discharge end of the mill substantially centrally thereof and about which the grate sectors are assembled, and clamp bars for the grate sectors having a portion extending into the mill beyond the inner face of the grate sectors and cooperating with said conical member to free the grate surface of oversize and reducing mediuln.

9. A mill comprising a rotatable drum or barrel adapted to receive a load of freely movable reducing bodies and material to be reduced. a conical member at the discharge end of the mill, and means disposed radially of the discharge end and co-operatiug with said conical member to effect a deflection of the oversize and reducing medium in a direciorg opposed to the normal travel of the mill 10. In a mill of the class described the combination of a rotary drum or barrel having a feed head and a discharge head, grate sectors loo at the discharge end of the mill, clamp bars for said grate sectors, said clamp bars extending inwardly of the mill beyond the inner face of the grate sectors, the leadingface of said lnwardly extending portions being concaved, the extension of the bar and the concaved portion thereof cooperating with the grates to move the oversize of the load away from the grates.

11..In a mill of the character described the combination of a rotary drum or barrel, grate sectors at the discharge end of said barrel, a conical member about which the grate sectors are assembled, and clamp bars for holding said grate sectors in place, each of sald clamp bars projecting inwardly beyond the inner face of the grate sectors and having lts leading edge or face concaved to effect a movement of portions of the mill load along the face of said conical member and away from the grate sectors during the rotation of the mill.

12.. As an article of manufacture, a grateretalning clamp bar for grate mills, provided with a load dctlecting portion.

13. As an article of manufacture, a grateretaining clamp bar for grate mills, provided With a load deflecting extension having its leading edge or face concaved.

14. A mlll comprising a rotatable drum or barrel, a grate at the discharge end of the said drum or barrel and liners for said drum extending substantially from end to end thereof and sloping toward the Grate on the ascending side of the mill drum during rotation of the mill drum, for migrating the mill load toward the grate during the rotation of said drum or barrel. i

15. A mill comprising a rotatable drum or barrel, ada ted to receive a load of freely movable reducing bodies and material to be reduced and sloping liners extending substantially from end to end of said mill drum, to effect a migration of the mill load toward the 'discharge end of the drum.

16. A mill comprising a rotatable drum or barrel and liners for said drum or barrel adapted to conftm to the interior'of the drum and sloping toward the discharge end on the ascending side thereof for migrating the mill load toward said discharge end during the rotation of the drum or barrel.

17. A mill comprising a rotatable drum or barrel adapted to receive a load of freely movable reducing bodies and material to be reduced, a grate at the discharge end of said drum and spiral liners disposed on the interior of said ydrum and sloping toward said grate on the ascending side of the mill drum and extending to the operative zone thereof to effect migration or movement of the mili load toward the rate.

18. In a mili tifie combination of a rotary drum or barrel, a grate adjacent the 'discharge end thereof and lead deecting means contiguousthe grate and cooperating with said grate on the rising side of the drum for freeing the grate surface of oversize.

19. In a mill the combination of a rotary drum or barrel, liners for said drum or barrel sloping toward the 'discharge end on the ascending side of the drum or barrel to effect a. movement or migration of the mill load toward the discharge end of said drum or barrel and load deflecting means contiguous the discharee end for effecting a counter movement of the mill load during rotation of the said drum or barrel.

20. In a mill the combination of a rotary drum or barrel, a grate adjacent the discharge end thereof, liners for said drum or barrel sloping toward said grate on the ascending side of the druln to effect migration or travel of the mill load toward said grate and deflecting means contiguous the grate and operable to effect a counter movement of the mill load away from the grate during the rotation of said drum or barrel.

21. In a mill the combination of a rotary drum or barrel, a grate adjacent the discharge end of said/drum or barrel, and means on the wall of the drum for effecting, during the rotation of said drum, a cascading movement of the mill load, movementl or migration of the mill load toward the grate, and means adjacent the grate for effecting a lateral movement of the oversize of the load toward the central part of the mill in a direction away from the grate.

22. As an article of manufact-ure an integral spiral liner section for mills of the rotary drum type adapted,y to have a spiral Wearing surface and slope toward the discharge end of the mill drum on the ascending side of the drum, the spiral Wearing surface being in a direction to move the charge contacting thexewith toward the discharge end of the mil 23. As an article of manufacture an integral spiral liner section for mills of the rotary drum type shaped on one face so as to conform to the interior of the mill drum, to slope toward the discharge end of the drum and to extend substantially from end to' end thereof.

24. A liner section for mills of the rotary drum type, one face of the liner being so shaped as to lie along and contact throughout its length with the interior of the mill drum.

another face of said liner being given a spiral formation sloping toward the discharge end of the drum on the ascending side of the drum, the spiral being in a direction to move a. charge contacting therewith toward the discharge of the mill.

25. A mili comprising in combination a rotary drum or barrel having a feed end and a discharge end, and radial deiectors ad'acent the discharge end of the mill, said cectors extending inwardly aad laterally f drum or barrel, a feedhead therefor, a grate lll adjacent the discharge end of the mill, and

elongated deflecting members. adjacent the grate and having their long axis extending radially thereof,said membeis projecting inwardly of the mill and beyond the inner face of the grate and laterally with respect-thereto, the lateral projection of said deflecting members being in a rearward direct-ion with respect to the direction of rotation of the mill drum.

27. In a mill of the character described, the combination of a rotary drum or barrel, having a feed end and a discharge end, a grate adjacent the discharge end, and perforated load-deflecting members positioned adjacent said grate and cooperating there.- with.

28. AS an article of manufacture, a clamp bar for 'mills provided with a laterally extendingr load-dellecting portion.

29. As an article of manufacture, a clamp bar for grates of grate mills provided with a perforated laterally extending load deflecting portion.

30. In a mill' of the class described, the combination of a rotary drum or barrel adapted to receive a load of freely movable reduc-ing bodies and material to be reduced. a feed head and a discharge head for said drum, a grate adjacent to and facing the discharge head and disposed transversely of the mill drum, and load-dellecting means adjacent said grat-e and extending therefrom inwardly of the mill and laterally with respect to the grate.

31. In a mill of the class described, the combination of a rotary drum or barrel, a feed head and a discharge headv therefor, a grate adjacent the discharge head and exf tending transversely of the drum, deflecting means within the mill adjacent the feed head and adjacent the discharge head, the deflecting means adjacent the discharge head projecting inwardly of the mill from the inner face of the grate and then laterally to overlie a port-ion of the grate.

32. A mill comprising in combination a rotary druml or barrel, a grate for said drum extending transversely of the drum, reducing media within the drum or barrel, and deflecting means lying along the inner face of said grate andv extending inwardly therefrom and then laterally with respect to the grate to partially overlie-the grate at an angle to the plane of the grate for freeing the grate of reduc-ing media.

33. In a mill the combination of a rotary drum or barrel, a feed head and a discharge head therefor, asectional grate adjacent the fccil head and clamp bars for holding the sections of the grate in place, said bars extending inwardly out of the plane of the grate and laterally to overlie a portion of the inner face of the grate.

34. In a mill, the combina-tion of a rotary drum, a feed head and a discharge head therefor, a sectional Grate adjacent the discharge head, clamp tbars for holding said grate sections in place, said bars extending inwardly of the mill out of the plane of the grate and laterally with respect to the inner face of the grate, so as to overlie a portion thereof, said overlying portion being perforated.

35. In a mill, the combination of a rotary drum, a feed head and a discharge head therefor, sectional liners for the feed head, a sectional grate adjacent the discharge head, clamp bars for retaining the feed head liners in place, said bars extending inwardly of the mill out of the plane of the liners and laterall to overlie a portion of the liners, clamp arsfor retaining thel grate sections in place, said clamp bars extending inwardly of the mill out of the plane of the grates and laterally to overlie a portion of the grate, the two sets of clamp bars cooperating to effect movement of the mill load.

This specification signed this 31st day of May, 1927.

FRANK E. MARCY.A 

